Nickel Catalyst Ethylene Dimerization Butene-1 Selectivity
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Solution Overview
Problem
Existing processes for dimerizing ethylene into butene-1 suffer from inefficiencies in yield and selectivity, with previous methods often resulting in lower production rates and mixed product distributions.
Innovation Solution
A catalytic composition comprising a nickel precursor with an oxidation state of +II, at least one phosphine ligand, and an activating agent, such as chlorinated or brominated hydrocarbylaluminum compounds, operating within a temperature range of 45°C to 250°C, with specific molar ratios of phosphine to nickel and activating agent to phosphine, enhances the selective production of butene-1.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing nickel-based catalytic systems with phosphine ligands are used for ethylene dimerization, then the process can proceed, but the yield and selectivity for butene-1 production are insufficient
Solution Approach 1:
The patent changes the oxidation state parameter of the nickel catalyst from 0 to +2, and optimizes the phosphine-to-nickel molar ratio parameter to between 0.5 and 5. These parameter changes result in improved butene-1 selectivity (at least 62%) and yield (at least 91%), resolving the contradiction between productivity and manufacturing precision.
2Productivity
If previous dimerization processes are used, then butenes can be produced, but the product distribution is mixed and the production rate is low
Solution Approach 1:
The patent optimizes key parameters including raising the nickel oxidation state to +2, adjusting the phosphine-to-nickel molar ratio to 0.5-5, and setting the reaction temperature between 20-250°C. These parameter changes achieve a production rate of at least 91% butene yield with stable product distribution (at least 62% butene-1 selectivity), resolving the contradiction between productivity and composition stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process achieves a butene (C4) yield of at least 91% and a butene-1 selectivity of at least 62%, significantly improving the efficiency and selectivity of butene-1 production compared to previous methods.
Implementation Method 1
The transformation of ethylene using a homogeneous nickel catalyst has been studied since 1950. This research has led to the development and commercialization of different processes.
Data Source
AI summary
The invention relates to a method for the dimerisation of ethylene into butene-1 carried out with a catalytic composition comprising: at least one nickel precursor with a degree of oxidation (+II); at least one phosphine ligand of formula PR1R2R3, in which groups R1,R2 and R3 may be identical or different and may or may not be bonded to one another; and at least one activating agent selected from the group containing the chlorinated or brominated compounds of hydrocarbylaluminium, either alone or in admixture, said composition having a molar ratio of phosphine ligand to nickel precursor of between 5 and 30 and a molar ratio of activating agent to phosphine ligand greater than or equal to 1.